Clinical reports and animal studies indicate that zinc may play a significant role in taste and smell function and that disorders of taste and smell may be related to zinc insufficiency. However, recent formal clinical trials and studies with animals have yielded mixed results. Unfortunately, none of the available animal studies on zinc have measured sensory threshold and clinical studies have been plagued by problems of sampling from patients with highly heterogeneous etiologies. We propose an animal model to assess the effects of zinc insufficiency on taste and smell. Rats will be trained on operant tasks to detect the presence of an appropriate stimulus and absolute behavioral thresholds will be determined under conditions of zinc insufficiency and after dietary supplement with zinc. Separate groups of animals will be used to assay tissue zinc levels as a function of time on diet and these measures will provide parameters for the behavioral study. The proposed studies represent a cooperative effort between an animal psychophysical laboratory investigating chemical senses at The American University and a clinical diagnostic and treatment center for tast and smell disorders at Georgetown University School of Medicine.